Linq的小时总和(HH:MM) [英] Sum of hours (HH:MM) in Linq
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问题描述
我的数据库表中有"TimeClocked",格式为HH.mm,我想使用LINQ对所有"TimeClocked"求和.
I am having "TimeClocked" in my database table in the format HH.mm and I want to sum all the "TimeClocked" using LINQ.
我已经尝试过此聚合函数.
I have tried this aggregate function.
var data = _projectDbContext
.Tasks
.Where(x => x.Project.CompanyId == companyId && x.Status == true)
.Select(e => TimeSpan.Parse(e.TimeClocked))
.Aggregate(TimeSpan.FromMinutes(0), (total, next) => total + next)
.ToString();
我正在使用 EF Core 3.0.0 .它显示出这样的错误.
I am using EF Core 3.0.0. It's showing error like this.
Processing of the LINQ expression 'Aggregate<TimeSpan, TimeSpan>(
source: Select<TaskEntity, TimeSpan>(
source: Where<TaskEntity>(
source: DbSet<TaskEntity>,
predicate: (x) => x.Project.CompanyId == (Unhandled parameter: __companyId_0) && x.Status == True),
selector: (e) => Parse(e.TimeClocked)),
seed: (Unhandled parameter: __p_1),
func: (total, next) => total + next)' by 'NavigationExpandingExpressionVisitor' failed. This may indicate either a bug or a limitation in EF Core. See https://go.microsoft.com/fwlink/?linkid=2101433 for more detailed information.
任何帮助将不胜感激.
推荐答案
It happens due to restricted client evalution in EF Core 3
so you have to call AsEnumerable
right before untranslatable expressions
var data = _projectDbContext
.Tasks
.Where(x => x.Project.CompanyId == companyId && x.Status == true)
.AsEnumerable() // switches to LINQ to Objects
.Select(e => TimeSpan.Parse(e.TimeClocked))
.Aggregate(TimeSpan.FromMinutes(0), (total, next) => total + next)
.ToString();
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